It is argued that a concept of substance is possible which not only avoids metaphysical blind alleys but is worthy of serious philosophical attention. Starting with parker's notion of substance a conception is developed in which substance has the moments of haecceity, Logical independence, Causal independence, Causal efficacy, And conservation through change. Event and substance ontologies are compared and reasons for the superiority of the latter given. The results are related to the problem of personal identity, And it is suggested that a person's body may be identifiable by him by means of his person rather than the converse